Ah yes, the archetypical 80s comedy that refuses to be funny. Instead of laughs, you get a sad, little schmuck who turns his life around and screws up just about everything he undertakes. Unpleasant characters and setbacks lie at the core of the comedy, dreary performances and bland writing take care of the rest.
When David tells off his boss after a missed promotion, he is immediately fired. This gets him thinking, and that same night he tells his wife that he wants to leave their old lives behind and tour the country with the money they've saved. Their marriage is in a rut, so she obliges right away.
Albert Brooks isn't all that great in the lead, his directorial skills are negligible too. There are no funny or interesting characters, the situations they get themselves in are pretty boring and the vibe is just drab from start to finish. At least it stopped short of 90 minutes, that was by far the smartest choice Brooks made.